[NRF52] Question about the MBR and SD dependence

[shaba]

Hey folks,

Is there any dependence between the MBR and the SD version? The reason I ask is because we are working on a product that will be able to update the softdevice as well as the app portions of the image while ideally retaining the MBR.

Do you guys see any issues with this method? We are currently running the 2.0.0 version of the 332 SD with the 2.0.0 MBR. I was going to try downgrading just the first page of flash to the old MBR, but figured I would pose the question in parallel.

[bjorn-spockeli]

No, the MBR is SoftDevice independent, so the approach you're describing should work just fine. In fact, this is how we do it in our bootloader, the MBR is never updated during DFU, just the Softdevice.

-Bjørn

[bjorn-spockeli]

Yes, the MBR is never updated during a Device Firmware Update when using the bootloader from our SDK. Because we never update the MBR we also guarantee that the MBR will be compatible with all future SD versions. Leaving the MBR intact is therefore no issue, but you will have to update the bootloader so that its compatible with the API of the new SoftDevice.